Portable power driven grinding tool



Jan. 21, 1941. w. w. NASH PORTABLE POWER DRIVEN GRINDING TOOL Filed Jan.2, 1940 2 Sheets-Sheet l 'INVENTOR. Mum/v V/ A/4J7/ ATTORNEY.

Jan. 21, 1941. w; w NASH 2,229,598

PORTABLE POWER DRIVEN GRINDING TOOL Filed Jan. 2, 1940 2 Sheets-Sheet 2ll-llllh IN VENT OR. Mum/v h! Mar/7' ATTORNEY.

Patented Jan. 21, 1941 UNETED STATES PATENT OFFICE.

PORTABLE POWER DRIVEN GRINDING TOOL Application January 2, 1940, SerialNo. 312,039

8 Claims.

This invention relates to portable power driven grinding and like tools.

The main purpose and object of my invention is to provide such toolswith suction producing means for removing and collecting the abrasivedust generated in the use of the tools so that each tool will beequipped with its own dust remover and collector as a complete andintegral part thereof.

10 A further object of my invention is to drive the suction producingmeans by the same motor with which the tool is provided to drive thegrinding wheel and thus simplify and compact the tool structure for easein handling and ma- 15 nipulation.

In furtherance of the foregoing object, a shaft is provided in the toolstructure for drivingthe suction producing means and said shaft isdriven by the tool spindle on which the grinding wheel 20 is mounted fordirect drive, the spindle and the shaft being preferably arranged insubstantially parallel relation to locate the suction fan and thegrinding wheel at the front end of the tool.

The invention consists further in the features 25 hereinafter describedand claimed.

In the accompanying drawings Fig. 1 is a side elevational view of aportable power driven grinding tool provided with an abrasive dustremover and collector in accord- 30 ance withmy invention;

Fig. 2 is a front view of the tool with parts broken away and insection, respectively, to show some of the details of the constructionat the hood end of the tool;

35 Fig. 3 is a top plan View of the assembly shown in Fig. 2, partsbeing broken away and in section, respectively, for illustrativepurposes; and

Fig. 4 is a longitudinal sectional view of the tool on a larger scale toshow the driving con- 40 nection from tool spindle to the fan shaft.

As shown in the drawings, the tool has a body section composed of amotor section I and handle and gear case sections 2, 3 secured togetherin end to end relation with the handle section 45 at the rear end of thetool and the gear case section at the front end of the tool. The motorcase I contains an electric motor 4, as shown in Fig. 4, while thehandle 2 extends rearwardly from a switch casing 5 at the rear end ofthe 50 motor case I and containing a switch mechanism for turning on andoff the electric current to the tool motor in the use of the tool. Theswitch device has an actuator E accessible from the tool handle as shownin Fig. 1.

55 The armature shaft 1 of the motor extends into the gear case section3 and is there provided with gear teeth 8 which are in constant meshwith a gear pinion 9 fixed on the tool spindle l and an idler gear IImounted on a countershaft I2 supported in an upwardly extending portionI3 of the gear case section 3 as shown in Fig. 4. The idler gear IImeshes with a gear pinion It on a fan shaft I journaled in saidextension I3 in ball bearings I6, I6 as shown. The shaft I5 mounts asuction fan I! on its forward end, said 10 fan being directly driven bysaid shaft and located within a fan housing I8 secured by screws or thelike to the forward side of the extension I3 as disclosed herein.

The gear case 3 has a lower portion I9 extending forwardly of the upperportion I3 to the front end of the tool and there supporting a hood 29over a grinding wheel 2| mounted for direct drive on the front end ofthe spindle It in the hood as shown. The spindle I0 is journaled in saidextension I9 on ball bearings 22, 22, one in the extension and the otherin the gear case section next to the pinion 9. The spindle I6 is locatedwithin a sleeve in the extension I9 and includes torque responsiveblades 23 25 as in the prior patent to F. P. Forss, No. 2,112,695,granted March 29, 1938.

The hood 20 encloses the greater portion of the grinding wheel 2| and isopen on its underside so that the grinding wheel may extend below thehood for contact with work in the use of the tool.

The hood 20 is provided with a suction passage 24 having an intakeopening 25 at its lower end at the lower edge of the hood on the sidethereof towards which the grinding wheel rotates as indicated by thearrow a in Fig. 2. This locates the opening 25 in the direction in whichthe material loosened by the grinding wheel 2| is projected tangentiallytherefrom during a grinding action. Hence, the intake opening 25 crossesthe path of the abrasive dust so that the suction effort of the fan I!will draw the dust into the passage 24 for removal to a collectionreceptacle 26 with which the tool is equipped on the discharge side ofthe fan. The receptacle 26 is carried by the tool and is preferably inthe form of a bag of a non-inflammable material as will presentlyappear.

The passage 24 widens axially of 'the tool as it reaches the top of thehood 20 and there provides an enlarged chamber 21 extending beyond therear side of the hood for connection with an intake opening 28 in thefront wall of the fan housing I8 as shown. The opening 28 is in linewith the axis of the fan, the latter being of the center intakecentrifugal suction type having blades 29 which discharge peripherallyinto an outlet conduit 30 connected to the fan housing and extendingupwardly therefrom. The upper end of this conduit mounts the bag 26, acoupling 3| serving as a releasable connection between them. Thisenables the bag to be removed for emptying and cleaning.

Inasmuch as particles taken into the suction passage 2 3 are likely tobe aglow from the heat of friction from the abrading action, the bag 26is preferably made of Woven glass fibers to prevent.

injury by the heated particles. The bag is flexible and is sufficientlyporous to be distended by the air stream discharged into the same by thefan and hence assumes a more or less upright position while the tool isin operation. The bag may be equipped with a bracing structure to holdit from collapsing when the tool is not in use.

The front wall 32 of the hood may be hinged to the hood body as at 33 asshown in Fig. 2. This enables the hood to be readily opened when it isdesired to change or replace the grinding wheel 2!. The wall 32 isprovided with an opening 34 to pass a nut 35 which clamps the wheel onthe front end of the spindle l0.

The hood 20 is equipped with flexible deflectors 36, 3! along and at theouter end of the intake opening 25, respectively, to prevent theabrasive dust escaping from the suction effort of the fan IT. Thedeflector 36 parallels the opening 25, while the deflector 31 istransverse thereto on the front side of the hood. Both defiectors may bemade of resilient rubber material and extending below the lower edge ofthe hood contact with the work when the grinding wheel is pressedagainst the same. This is depicted in Fig. 2, the deflectors being shownengaging the work and serving to keep the dust particles within thesuction effort of the fan. The deflectors may be secured to the hood asshown.

As illustrated in Fig. 2, the hood has a slot 38 in its top wall 39 atthe rear end of the suction passage 24. This slot has a downwardlyextending flange 49 to deflect into the suction passage any particleswhich may be carried around with the wheel beyond the influence of theintake opening 25. V 7

Having the suction means driven by the same motor which drives thegrinding wheel as herein disclosed, eliminates the need for a separatemotor to drive the suction fan. This simplifies the tool structure andmoreover makes for compactness which promotes portability and ease inmanipulation. Grinding tools of the character depicted are usuallyequipped with high frequency motors. This gives the tool increased speedand power. In practice these motors operate on a'continuous load atabout 2 H. P. On momentary loads they operate at about 4 H. P. Takingthe drive for the suction fan from the tool motor provides ample powerfor operating both the fan and the grinding wheel as the fan requiresless than H. P. to drive it. Hence, with my novel driving arrangementthe tool motor may efiectively drive both the fan and the grinding wheelwithout diminishing the power factor for the grinding wheel.

While the tool referred to herein is portable and may be so used, yet inpractice along production lines as in automotive fender grinding andbody work, the tool is usually suspended from an overhead support by aspring biased counter-balancing device. Part of this equipment is shownin Fig. 1 wherein the cable 4| has a yoke 42 for attaching the cable tothe tool for suspending it above the place of use. The arms of the yokestraddle the tool case from above and have trunnion connections 43 attheir lower ends with the outer ring 44 of a swivel fixture whichencircles the tool case and is fixed thereto at a balancing pointbetween its ends. The inner ring 45 of this fixture is fixed to the toolcase and the bearing balls 46 of the fixture are between the rings asshown. The pivots 43 and the bearing balls 46 provide a universalmounting for the tool, that is, the pivots allow for tilting of the toolvertically, while the balls allow for a bodily rotation about the toolaxis.

This gives the tool while suspended the flexibility necessary for thegrinding wheel to reach all portions of the work.

The yoke 32 is provided above the tool case with a curved section 41which extends towards the rear end of the tool to provide a space forthe outlet conduit 36 when the tool is swung about its pivots 43 towardsthe yoke. In Fig. 2, the work indicated at 48 represents a motor vehiclefender, the outer surface of which is smoothed by grinding to take a.coating of paint.

The gearing which drives the fan shaft I is geared up for speed and inthe embodiment shown herein produces a vacuum of between 4 and 5 inchesat the suction intake 25. It will be noted that the intake 25 is withinthe width of the hood 20, while the passage 24 Widens out from thiswidth. This increases the velocity of the air as it is drawn into theintake 25 by the fan to create the suction effort required for removingthe albrasive dust. The deflectors 36, 31 also house the loosenedparticles and keep them from escaping into the surrounding atmosphere.With my invention, each tool is equipped with its own abrasive dustremover and collector, and thus the operator and the other workmen inthe region of the grinding operation are protected from breathing in thefine particles of this abrasive dust. In the drawings, the hood 20 isshown as having a split collar on its rear side for clamping the hood tothe extension [9.

The details of construction and arrangement of parts shown and describedmay be variously changed and modified without departing from the spiritand scope of my invention, except as pointed outin the annexed claims.

I claim as my invention:

1. In a portable power driven grinding tool having a body section, aspindle and a. fan shait journaled in said body section in substantiallyparallel relation, a motor connected tothe body section and having apower shaft extending into the body section between the fan shaft andthe spindle, means operatively connecting said power shaft to thespindle and the fan shaft for driving the same, a grinding wheel mountedfor direct drive on the spindle, a hood carried by the body section forthe grinding wheel and providing a chamber to partially house the same,means providing a suction passage at the hood independently of andopening into said chamber adjacent to the grinding wheel at the loweredge of the hood for removing the abrasive dust produced by the grindingwheel in the operation thereof, a suction fan in said passage and drivenby said fan shaft, and a dust collecting receptacle connected to saidpassage on the discharge side of the fan.

2. In a portable power driven grinding tool having a body section, aspindle and a fan shaft journaled in said body section in substantiallyparallel relation, a motor secured to the body section and having apower shaft extending into the body section between the spindle and thefan shaft, said power shaft having gear teeth at its end within the bodysection, gear pinions fixed to the ends of the spindle and the fan shaftadjacent to the power shaft, one of said gear pinions being in mesh withthe teeth on the power shaft for direct rotation thereby, gear wheelmeans journaled in the body section and in mesh with the other gearpinion and the teeth on the power shaft to be driven thereby, a grindingwheel mounted for direct drive on the front end of the spindle, a hoodcarried by the body section for said grinding wheel and providing achamber to partially house the same, means providing a suction passageat the hood independently of and opening into said chamber adjacent tothe grinding wheel at the lower edge of the hood for removing theabrasive dust produced by the grinding wheel in the operation thereof, asuction fan in said passage and driven by the fan shaft, and a dustcollecting receptacle connected to said passage on the discharge side ofthe fan.

3. In a portable power driven grinding tool having a body sectionprovided with upper and lower portions, the lower portion extendingbeyond the front end of the upper portion and providing therebetween arecess on the outer side of the tool, a spindle and a fan shaftjournaled in said lower and upper portions, respectively, insubstantially parallel relation, a motor secured to the rear end of thebody section and having a power shaft extending into the body sectionbetween the spindle and the fan shaft, means operatively connecting thepower shaft to the spindle and the fan shaft for driving the same, agrinding wheel mounted for direct drive on the front end of the spindle,a hood carried by the lower portion of the body section for the grindingwheel and providing a chamber to house the same within the hood, saidchamber being open on its under side for the grinding wheel to extendpartially ibBlOW the hood, a fan housing carrled by the body section insaid recess and containing a suction fan driven by the fan shaft, saidhousing having an inlet opening on the intake side of the fan and adischarge opening on the discharge side of the fan, means providing asuction passage at the hood independently of said chamber for removingthe abrasive dust produced by the grinding wheel in the operationthereof, said passage having a suction intake opening into said chamberat the lower edge of the hood adjacent to the grinding wheel and anoutlet at the recess and connected with the intake of the fan housing,and a dust collecting receptacle connected to the discharge opening ofsaid housing.

4. In a portable power driven grinding tool having a body section, aspindle and a fan shaft journaled in said body section in substantiallyparallel relation, a motor connected to the rear end of the body sectionand having a power shaft extending into the body section between the fanshaft and the spindle, means operatively connecting the power shaft tothe spindle and the fan shaft for driving the same, a grinding wheelmounted for direct drive on the front end of the spindle, a hood carriedby the body section for the grinding wheel and providing a chamber tohouse the same within the hood, said chamber being open on its underside for the grinding wheel to extend partially below the hood, asuction passage carried by the hood independently of said chamber andhaving a suction intake opening into said chamber at the lower end ofthe hood adjacent to the grinding wheel for removing the abrasive dustproduced by the grinding wheel in the operation thereof, a suction fanin said passage and driven by said fan shaft, a dust collectingreceptacle carried by the tool and connected to said passage on thedischarge side of the fan, and flexible dust deflectors carried by thehood and extending below the hood at said suction intake.

5. In a portable power driven grinding tool having a body section, aspindle and a fan shaft journaled in said body section in substantiallyparallel relation, a motor secured to the body section and having apower shaft extending into the same, means operatively connecting thepower shaft to the spindle and the fan shaft for driving the same, agrinding wheel mounted for direct drive on the spindle, a hood carriedby the body section for said grinding wheel and providing a chamber topartially house the same within the hood, said chamber being open on itsunder side for the grinding wheel to extend below the hood, a suctionpassage carried by the hood independently of said chamber and having asuction intake opening into said chamber at the lower edge of the hoodadjacent to said grinding wheel for removing the abrasive dust produced'by the grinding wheel in the operation thereof, a fan in said passageand driven by said fan shaft, said passage increasing in width from itsinlet to its outlet end at the intake side of the fan, and a dustcollecting receptacle carried by the tool and connected to said passageon the discharge side of the fan.

6. In a portable power driven grinding tool having a body section, aspindle and a fan shaft journaled in said body section in substantiallyparallel relation, a motor connected to the body section and having apower shaft extending into the body section between the fan shaft andthe spindle, means operatively connecting the power shaft to the spindleand the fan shaft for driving the same, a grinding wheel mounted for direct drive on the spindle, a hood carried by the body section over thegrinding wheel, a suction passage carried by the hood on the outer sidethereof and having an intake opening at its lower end adjacent to thegrinding wheel for removing the abrasive dust produced by the grindingwheel in the operation thereof, a suction fan in said passage and drivenby said fan shaft, said hood having a slot therein at the end of thepassage adjacent to the fan, a flange at said slot in the space betweenthe hood and the grinding wheel for deflecting dust carried around withthe grinding wheel into the suction passage for removal by the fan, anda dust collecting receptacle connected to the passage on the dischargeside of the fan.

7. In a portable power driven grinding tool having motor, gear case, andhandle sections connected together in end to end relation with the motorsection intermediate the gear case and the handle sections, a spindleand a fan shaft journaled in the gear case section in substantiallyparallel relation, an electric motor within said motor section andhaving an armature shaft extending into the gear case section betweenthe spindle and the fan shaft, gearing in the gear case sectionoperatively connecting the armature shaft to the spindle and the fanshaft for driving the same, a grinding wheel and a suction fan mountedfor direct drive on the spindle and the fan shaft, respectively,adjacent to the front end of the tool, a housing secured to the gearcase section for the fan, a hood carried by the gear case section forthe grinding wheel and providing a chamber to partially house the same,a suction passage at the hood independently of said chamber for removingthe abrasive dust produced by the grinding wheel in the operationthereof, said passage having an intake opening into said chamberadjacent to the grinding wheel at the lower edge of the hood and anoutlet opening connected to the fan housing on the inlet side of thefan, and a dust collecting receptacle carried by the tool and connectedto the fan housing on the discharge side of the fan.

8. In a portable power driven grinding tool having a body section, aspindle and a fan shaft journalled in said body section, a motor securedto said body section and having an operative connection with the spindleand the fan shaft for driving thesame, a grindingwheel mounted fordirect drive o-nthe spindle exteriorlyof the bodysection, a hood carriedby the body section for the grinding wheel and providing a chamber topartially house the same with the grinding wheel extending out of thehood at the lower edge thereof, said hood being provided with a suctionpassage independently of said chamber and following along the same atthe periphery of the wheel from the lower edge of the hood to the upperportion thereof above the grinding wheel, said passage having its outletopening adjacent the upper end of the hood, a suction fan connected tosaid outlet opening and driven by the fan shaft, and a dust collectingreceptacle connected to said passage on the discharge side of the fan.

WILLIAM W. NASH.

